In recent years, thanks to Internet, optical fiber communication has been widespread in the world. People require increasingly more information than the current transmission media may load, so optic fiber is the only one choice.
Dense Wavelength Division Multiplexing is very essential in the field of optic fiber communication, in order to transmit data each other; referring now to FIG. 3, a general idea of a bi-directional transmission of a combination of station A and station B is mentioned in U.S. patent application Ser. No. 6,339,487, in which station A has a station A receiver 360 and a station A transmitter 370 separately and a station A filter 304 is linked between the station A receiver 360 and the station A transmitter 370; further, station B has a station B receiver 360′ and a station B transmitter 370′ separately, in which a station B filter 304′ is linked between the station B receiver 360′ and the station B transmitter 370′ and an optic fiber 350 is linked between said station B filter 304′ and said station A filter 304; in order to transmit data, the transmitter 370 of said station A and the transmitter 370′ of said station B may transmit optic transmission data of different wavelength, respectively, to the station A receiver 360 and the station B receiver 360′ using a filter processing signal. Such a transmission idea is a quite good one.
In consideration of the idea, the inventor actively researches and designs it and finally develops the multiplexer with the DWDM function.